Datolith
| Datolith | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | CaB [OH | SiO 4 ] (or CaB [4] [OH | SiO 4 ]) |
|
Mineral class (and possibly department) |
Silicates and Germanates |
|
System no. to Strunz and to Dana |
9.AJ.20 ( 8th edition : VIII / B.29) 54.02.01a.01 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | P 2 1 / c (No. 14) |
| Lattice parameters |
a = 4.836 Å ; b = 7.61 Å; c = 9.64 Å β = 90.4 ° |
| Formula units | Z = 4 |
| Frequent crystal faces | {100}, {001}, {110}, {111}, {011}, {012} and others |
| Physical Properties | |
| Mohs hardness | 5 to 5.5 |
| Density (g / cm 3 ) | measured: 2.96 to 3.00; calculated: [3.00] |
| Cleavage | no |
| Break ; Tenacity | shell-like to uneven |
| colour | colorless, white, gray, yellow, green, pink to red |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss, weak resin gloss on broken surfaces |
| Crystal optics | |
| Refractive indices |
n α = 1.626 n β = 1.653 to 1.654 n γ = 1.670 |
| Birefringence | δ = 0.044 |
| Optical character | biaxial negative |
| Axis angle | 2V = 74 ° |
| Other properties | |
| Special features | blue fluorescence under short-wave UV light |
Datolith is a mineral from the mineral class of " silicates and germanates " with the chemical composition CaB [OH | SiO 4 ] and chemical point of view, a calcium - boron silicate, more particularly to a Calciumboratosilikat with hydroxide ions as additional anions .
Datolith crystallizes in the monoclinic crystal system and develops short columnar or thick tabular crystals up to 12 centimeters in length, but is often also found in the form of grape to spherical, granular or massive mineral aggregates . Undamaged or unweathered crystal surfaces have a glass-like gloss , whereas fractured surfaces have a slightly resin-like shimmer. In its pure form, Datolith is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline formation, it can also be translucent white and, due to foreign admixtures, take on a gray, yellow, green or pink to red color.
Etymology and history
The name Datolith is composed of the Greek word δατέομαι [detéomai] for "divide or distribute" and λίθος [lítʰos] for "stone" and refers to the readily divisible of the often occurring, crumbly mineral aggregates.
The mineral was first discovered and described in 1805 by Jens Esmark (1763–1839) in the "Nødebro" mine near Arendal in the Norwegian province of Aust-Agder .
classification
In the meanwhile outdated, but still common 8th edition of the mineral systematics according to Strunz , the datolite belonged to the division of " island silicates with non-tetrahedral anions (Neso-Subsilicates)", where together with Bakerite , Calcybeborosilit- (Y) , Gadolinit- (Ce) , Gadolinit- (Y) , Hingganit- (Ce) , Hingganit- (Y) , Hingganit- (Yb) , Homilit and Minasgeraisit- (Y) the "Datolite-Gadolinit-Gruppe" with the system no. VIII / B.29 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also classifies the datolith in the category of "island silicates (nesosilicates)". This is, however, further subdivided according to the possible presence of further anions and the coordination of the cations involved , so that the mineral is classified according to its composition in the subsection " Island silicates with BO 3 triangles and / or B [4] , Be [4] tetrahedra, corner-dividing with SiO 4 "is to be found, where it is found together with bakerite, calcybeborosilite- (Y), gadolinite- (Ce), gadolinite- (Y), hingganite- (Ce), hangingganite- (Y), hangingganite- (Yb) , Homilit, Melanocerit- (Ce) and Minasgeraisit- (Y) form the unnamed group 9.AJ.20 .
The systematics of minerals according to Dana , which is predominantly used in the English-speaking area , also classifies the datolith in the more finely subdivided division of "island silicates: borosilicates and some beryllosilicates with (BO 3 )". Here he is the namesake of the " Datolith group (Datolith series) " with the system no. 54.02.01a and the other members Hingganit- (Ce), Hingganit- (Y), Hingganit- (Yb) and Calcybeborosilit- (Y) within the subsection “Island silicates: borosilicates and some beryllosilicates with B in [4] coordination” Find.
Crystal structure
Datolith crystallizes monoclinically in the space group P 2 1 / c (space group no. 14) with the lattice parameters a = 4.836 Å , b = 7.61 Å, c = 9.64 Å and β = 90.4 ° and 4 formula units per Unit cell .
properties
In front of the soldering tube , the datolith melts into a clear pearl while foaming and colors the flame green. In hydrochloric acid it takes on a gelatinous consistency.
Some datolites show a blue fluorescence under short-wave UV light .
Modifications and varieties
Botryolite (also fiber datolite ) is a grape-shaped variety of datolite.
As Haytorit one is Pseudomorphose of Chalcedon referred to Datolith.
Education and Locations
Datolite forms either in metamorphic rocks or through hydrothermal processes , but can also be found in volcanic rock, on ore veins, in pegmatites or on amethyst inside chalcedony balls. The accompanying minerals include axinite , calcite , danburite , garnets , prehnite and zeolites .
As a rather seldom occurring mineral formation, Datolith can sometimes be abundant at different sites, but overall it is not very common. So far (as of 2012) around 460 sites are known. The mineral was found at the following sites, among others: Tasmania (Colebrook Hill) near Australia; Hubei , Yunnan and Zhejiang in China; in many regions of Germany (including Sankt Andreasberg and Niederkirchen (West Palatinate)); Alsace and Lorraine in France; England and Scotland in Great Britain; Italy ; Hokkaidō , Kyūshū and Shikoku Japan; Kazakhstan ; Ontario (Hastings County) and Quebec (Argenteuil County) in Canada; Meknès-Tafilalet and Souss-Massa-Daraâ in Morocco; Guanajuato and San Luis Potosí in Mexico; Namibia (Omaruru); New Zealand (North Island); North Korea ; among others on magnetic ore deposits in gneiss near Arendal in Norway ; Salzburg (Hohe Tauern), Styria (Eibegggraben) and Tyrol (Tauerntal, Theiss) in Austria; Poland ; some regions in Russia ; Sweden ; Switzerland (Grischun and Wallis); Slovakia ; Spain ; South Africa ; Tajikistan ; Ukraine ; Hungary ; many regions in the US (including Connecticut and Bergen Hill); as well as in Bohemia and Moravia in the Czech Republic.
See also
literature
- MH Klaproth: Chemical investigation of the datolith . In: New General Journal of Chemistry . tape 6 , 1806, pp. 107–110 ( available online at rruff.info [PDF; 255 kB ; accessed on March 12, 2019]).
- FF Foit, MW Phillips, GV Gibbs: A refinement of the crystal structure of datolite, CaBSiO 4 (OH) . In: American Mineralogist . tape 58 , 1973, p. 909–914 (English, 719 [PDF; accessed March 12, 2019]).
- Petr Korbel, Milan Novák: Mineral Encyclopedia (= Villager Nature ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 208 .
Web links
- Mineral Atlas: Datolith (Wiki)
- Datolite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed March 12, 2019 .
- American-Mineralogist-Crystal-Structure-Database - Datolite. In: rruff.geo.arizona.edu. Retrieved March 12, 2019 .
Individual evidence
- ↑ a b c d e Old mineral names and synonyms at indra-g.at: databases mineralogy, geology etc. (PDF 2.65 MB)
- ↑ a b c d Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 562 .
- ↑ David Barthelmy: Dato Lite MineralData. In: webmineral.com. Retrieved March 12, 2019 .
- ^ Helmut Schrätze , Karl-Ludwig Weiner : Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 701 .
- ↑ a b c d Datolite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 75 kB ; accessed on March 12, 2019]).
- ↑ a b c d e f Datolite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 12, 2019 .
- ↑ Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott Verlag, Thun 1979, ISBN 3-7225-6265-1 , p. 200 .
- ↑ Esmark (Esmarch), Jens. (1763-1839). In: mineralogicalrecord.com. The Mineralogical Record, accessed March 12, 2019 .
- ^ Paul Ramdohr , Hugo Strunz : Klockmanns textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 685 .
- ↑ RV Dietrich: Dato Lite. In: stoneplus.cst.cmich.edu. GemRocks, February 20, 2015, accessed June 4, 2020 .
- ↑ Localities for Dato Lite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 12, 2019 .